The project deals with energy consumption, evaporation of water and ventilation in indoor swimming baths. The relation between evaporation of water, temperature and air movement is studied by means of CFD and the energy consumption of existing swimming baths is analyzed to be used for a simulation model. Based on the findings a design guide for swimming baths is developed. The project is lead by Birch & Krogboe and funded by ELFOR, Dansk Eldistribution.